Sealable fuse-plug.



C. D: PLATT.

SEALABLE FUSE PLUG.

APPLICATION msu FEB.29, 1916.

1,226,808. Patented May 22,1917.

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CLARENCE I). PLATT, OF BRIDGEIEORT, CONNECTICUT.

SEALABLE FUSE-PLUG.

Specification of Letters Patent.

Patented May 22, 1917.

Application filed February 29, 1916. Serial No. 81,245.

To all whom it may concern.

Be it known that I, CLARENCE D. PLATT, a citizen of the United gtatcs,residing at Bridgeport, county of Fairfield, State of Connecticut, haveinvented an Improvement in Sealable Fuse-Plugs, of which the followingis a specification.

This invention relates to the class of fuse plugs commonly used for theprotection of small branch circuits and which are so con structed that afusible strip within the plug will either melt or blow when subjected toan excess of current and thus prevent injury to lamps or other 'deviceson the circuit beyond the plug. The use of fuse plugs is common, theyare inexpensive and can easily be obtained by anyone. As a result it isnot uncommon for fuse plugs to be deliberately changed by flat rateconsumers and plugs of greater carrying capacity substituted, or plugsare maliciously tampered with by unauthorized persons, resulting in theburning out of or serious injury to delicate devices or apparatus whichmay be in the cir- The fuse blocks for these plugs are usually adaptedto receive the plugs in pairs.

My invention therefore has for its object to provide simple andinexpensive means whereby, when the central station men have insertedthe proper plugs, they may be sealed in place, so that plugs of greatercarrying capacity cannot be substituted by customers for the purpose ofdefrauding the central station, and malicious tampering with the plugsby anyone is wholly prevented, as the plugs cannot be removed withoutbreaking the seals.

Another object of the invention is to provide simple and convenientscalable means for preventing the theft of current in unoccupiedtenements, stores, factories, &c., without removing the meter.

With these and other objects in view, I have devised the novel scalableplug which I will now describe, referring to the accompanying drawingforming a part of this specification and using reference characters toindicate the several parts:

Figure 1 is a perspective of the cap of either a fuse or dummy plugembodying my invention;

Fig. 2 a section on the line 2-2 in Fig. 1;

Fig. 3 a longitudinal section of a fuse plug embodying my invention;

F 4: an elevation partly broken away of a dummy plug embodying myinvention, and

Fig. 5 is a plan view of a fuse block with two of my novel plugs sealedtherein.

Fuse plugs as ordinarily constructed comprise a chambered body ofinsulating material, a cap 11 covering the chamber and provided with anopening 12, a disk of trans parent material, usually mica, and generallyknown as a mica window, closing the opening and retained in place by thecap, a contact tip 1 1 seated in the closed end of the body, a screwshell 15 and a fuse strip 16 which connects the contact tip with thescrew shell, is confined within the chamber of the plug and is visiblethrough the window. It will of course be understood that the specialdetails of construction of the plug are Wholly immaterial so far as thepresent invention is concerned. In carrying out my invention, I punchout straps from the metal of the cap, leaving both ends attached, andthus form eyes 17 to receive the wires or strips of seals. The caps aresecured in place in the usual manner by closing the edges of the capsunder the flanges of the bodies, as at 18, in Figs. 3 and 4E. 19 denotesa fuse block of ordinary construction. The bodies of my novel scalablefuses are turned into the sockets in the fuse blocks in the usualmanner, as clearly shown in Fig. 5. The seal comprises a wire or strip20 which is passed through eyes of contiguous fuse caps. One end of thewire or strip is ordinarily molded into a seal 21 of relatively softmetal, which is proyided with a hole through which the other end of thewire is passed after being passed through the eyes of two caps, themetal of the seal being then closed about the wire by a suitable punchwhich im presses suitable identifying marks into the seal to preventunauthorized removal and the substitution of another seal. As the use ofthis class of seals is common, fuller description is not thought to berequired. In fact, the special type of seal used is wholly immaterial sofar as the present invention is concerned. 22 in Fig. 4 denotes a dummyfuse body provided with a cap having eyes as before, which may be usedin lieu of a live fuse plug to prevent theft of current in unusedbuildings. Precisely the same result may be secured by using an ordinaryfuse that has been burned out or blown.

In case of a fuse block having three fuse plugs, the two outer plugs maybe sealed to the central plug. It Will thus be seen that by providingthe caps of fuse plugs With eyes, making them scalable, I have produceda plug which will effectually prevent theft of current, and will preventtampering with the plugs and damage to delicate apparatus from excess ofcurrent.

Having thus described my invention I claim 1. A fuse plug of thecharacter described comprising, in combination with a body of insulatingmaterial having an open chamber therein, a substantially transparentdisk closing the opening to said chamber, and a metallic cap adapted toretain said disk in place, said cap being provided With an integralbridging strap struck out from the metal of the outer face thereof,whereby an eyelet is formed for the reception and retention of a sealingstrand of flexible material.

2. In combination, a fuse plug, said plug comprising a body ofinsulating material having an open chamber therein, a substantiallytransparent disk closing the opening to said chamber, a metallic capadapted to retain said disk in place, said cap being provided With abridging strap struck out from the metal of the outer face thereofwhereby an eyelet is formed, a strand of flexible material passingthrough said eyelet and thus engaging said cap, another body throughwhich said strand is directed to engage the same, and means for sealingthe ends of said strand.

3. In combination, a plurality of fuse plugs, each plug comprising achambered body of insulating material having an open chamber therein, asubstantially transparent disk closing the opening to said chamber ametallic cap adapted to retain said disk in place, each of said capsbeing provided with a series of integral bridging straps struck out fromthe metal of the outer face thereof whereby eyelets are formed andcontiguous caps may be interlaced irrespective of the rotative positionsthereof, and a strand of flexible material interlacing said caps throughcontiguous eyelets, and means for sealing the ends of said strand.

In testimony whereof I afiix my signature.

CLARENCE D. PLATT.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents. Washington, D. 0.

